The Bronze Age generally runs parallel to the success of non-superhero DC Universe characters (like Swamp Thing) and slightly darker plotlines in mainstream books. The stories introduced more minority characters and dealt, sometimes maturely, with real world issues such as drug use. We also see the the first miniseries released during this period. The era extends from the early 1970s to the mid-1980s, ending at Crisis on Infinite Earths and the start of the Modern Age.